Vacuum assisted percutaneous appliance

ABSTRACT

A device for reducing agent penetration at an insertion site is provided that has a porous inner sleeve fluidly connected to a conduit. A vacuum or hydrodynamic source is fluidly connected to the conduit. The device is stabilized by fibroblast in-growth and inhibits bacterial colonization. 
     A device is also provided that has a conduit having a bore and an outer conduit surface. The outer conduit surface is optionally nanotextured to promote fibroblast adhesion and limit bacterial residency. A sleeve is provided in fluid communication with the bore of the conduit, and is formed from materials characterized by a pore matrix through which vacuum or hydrodynamic draw is achieved in a process to promote stabilization and reducing bacterial colonization by draw fluid from an area around the surrounding the site of the device. The sleeve optionally has a distal nanotextured surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Utility application Ser. No.13/394,239 filed Mar. 5, 2012 which in turn claims priority PCTApplication Serial No. PCT/US11/25958 filed Feb. 23, 2011 which in turnclaims priority of U.S. Provisional Patent Applications Ser. No.61/307,166 filed Feb. 23, 2010; Ser. No. 61/406,814 filed Oct. 26, 2010;and Ser. No. 61/419,491 filed Dec. 3, 2010, the contents of which areincorporated herein by reference.

FIELD OF THE INVENTION

The invention relates in general to percutaneous access and inparticular to processes and devices for preventing infection at the siteof percutaneous access. More specifically, the invention providesprocesses and devices for preventing internalization of bacteria, otherinfectious agents, or other unwanted materials from entering the accesspoint for a catheter, Steinman pin, Kirschner wires, or otherpercutaneous instruments.

BACKGROUND OF THE INVENTION

Intravenous catheters act as an attachment point for microorganisms,leading to biofilm formation and infection at the site of insertion oralong the surface of the device. Infection of the catheter hub andcatheter-related bloodstream infections are major complications forpatients with indwelling catheters (e.g., Safdar and Maki, IntensiveCare Med. 2004 January; 30(1):62-7; Saint et al., Infect Control HaspEpidemiol. 2000 June; 21(6):375-80).

Prior attempts at controlling catheter-related infection are directed tosterilization techniques such as by topical or fluidic antibacterialsapplied to the insertion site or integrated into the catheter itself.The antimicrobial activity of ethyl alcohol (ethanol) as well as otheralcohols is well known. Isopropyl alcohol at a concentration of 60-70%is widely used as an antimicrobial agent for sanitization of surfacesand skin. A concentration of 10% ethyl alcohol inhibits the growth ofmost microorganisms, while concentrations of 40% and higher aregenerally considered bactericidal (Sissons et al., Archives of OralBiology, Vol. 41, 1, JN 1996; 27-34).

Catheterization can be kept in place for as little as a few seconds fordrainage or delivery. It is increasingly common, however, forpercutaneous access such as peripherally inserted central catheters(PICC), skeletal guide wires, cardiac assist device lines, or otherinstruments to be kept in place for weeks or months. The increased timein which such devices are maintained across the skin increases thelikelihood of instrument related infection.

Thus, there exists a need for processes and devices to prevent or reducethe likelihood of infection related to percutaneous instruments.

SUMMARY OF THE INVENTION

A device for reducing agent penetration at an insertion site is providedthat includes a porous inner sleeve fluidly connected to a conduit. Avacuum or hydrodynamic source is fluidly connected to the conduit tocreate a fluid draw from the subject tissue through the inner sleeve tothe conduit. The conduit is readily formed to have a bore and an outerconduit surface, the outer conduit surface being optionallynanotextured. The conduit bore is adapted to accommodate a medicalappliance. The sleeve in fluid communication with the conduit is readilyformed of materials characterized by a pore matrix through which vacuumor hydrodynamic draw is achieved without collapse under the vacuum orhydrodynamic draw conditions.

A process for stabilizing an implanted device at a percutaneousinsertion site in subject tissue includes inserting the aforementioneddevice subcutaneously and drawing vacuum against the subject tissue atthe insertion site through the sleeve and the conduit or fluid from theinsertion site through said conduit to draw fibroblasts into and ontosaid sleeve to stabilize the implanted device.

A kit for reducing agent penetration at a percutaneous insertion site insubject tissue is provided that includes a gasket connecting to apercutaneous access device and a bandage attached to the gasket to forma pressure-tight seal around the insertion site. A conduit associatedwith the percutaneous access device is in fluid communication with thebandage and the subject tissue surrounding the insertion site. A vacuumor hydrodynamic draw against the conduit serves to reduce agentpenetration at the percutaneous insertion site in the subject tissue.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of an inventive device with therelative dimensions of aspects exaggerated for visual clarity;

FIG. 2 is a cross-sectional view of an inventive device with relativedimensions of aspects exaggerated for visual clarity depicting an outersleeve covering an inner sleeve for protection during skin penetration;

FIG. 3 is a cross-sectional view of an inventive device with relativedimensions of aspects exaggerated for visual clarity depicting a skinsurface terminating outer sleeve;

FIG. 4 is a perspective view of an inventive device employed with abandage providing a pressure seal to the outer surface of the skin;

FIG. 5 is a perspective view of an inventive device with relativedimensions of aspect exaggerated for visual clarity with an expandableouter sleeve;

FIG. 6 is a cross-sectional view of the relative dimensions of aspectsexaggerated for visual clarity depicting a pressure seal formed againstthe outer surface of the skin with resort to a gasket and a bandage;

FIG. 7A is a cross-sectional view of an inventive device with relativedimensions of aspect exaggerated for visual clarity depicting a siliconcollar and a plastic base forming a slidable pressure-tight seal againstthe outer surface of the skin;

FIG. 7B is a cross-sectional view of an inventive device with relativedimensions of aspect exaggerated for visual clarity depicting a siliconcollar and a plastic base forming a slidable pressure-tight seal againstthe outer surface of the skin; and

FIG. 8A is a perspective cross-sectional view of percutaneous componentsof inventive device with relative dimensions of aspect exaggerated forvisual clarity depicting a flanged inner sleeve and an optionalopen-celled, implant compatible velour cuff;

FIG. 8B is an exploded view of FIG. 8A; and

FIG. 9 is a partial cutaway view of a flanged inventive device withrelative dimensions of aspect exaggerated for visual clarity.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the preferred embodiment(s) is merelyexemplary in nature and is in no way intended to limit the scope of theinvention, its application, or uses, which may, of course, vary. Theinvention is described with relation to the non-limiting definitions andterminology included herein. These definitions and terminology are notdesigned to function as a limitation on the scope or practice of theinvention but are presented for illustrative and descriptive purposesonly. The inventive devices are disclosed herein in general with respectto a catheter, but this is not meant to be a limitation on theinvention. Any tube, instrument, wire, material or assembly thatpenetrates the skin of a subject is similarly operable for use with theinventive device or integral therewith.

The invention has utility as a device to reduce the likelihood ofpercutaneous instrument related infection.

An inventive device is intended for use with a percutaneous instrument.Any instrument that is intended to traverse the skin is operable withthe inventive device. The device is optionally used with a percutaneousaccess device illustratively a PICC, cannula, or other catheter, or pinillustratively a Steinman pin, Kirschner wires, and other devices orinstruments that penetrate the skin. It is appreciated that the deviceis similarly operable with bladder or other catheterization instrument.

The inventive devices decrease or prevent penetration or complicationsdue to the presence of an agent. As used herein an “agent” isillustratively: an infectious agent such as bacteria, virus, fungus,other organism; or foreign material. Illustrative examples of foreignmaterial include: bandage; soil; water, saliva, urine, or other fluid;feces; chemicals; or other matter known in the art. Illustrativeexamples of infectious agents that are prevented from penetrating orproduce complications include P. aeruginosa, E. cloacae; E. faecalis; C.albicans; K. pneumonia; E. coli; S. aureus; or other infectious agents.

An inventive device is optionally used on the epidermis of a subject. Asused herein, the term “subject” refers to a human or non-human animal,optionally a mammal including a human, non-primate such as cows, pigs,horses, goats, sheep, cats, dogs, avian species and rodents; and anon-human primate such as monkeys, chimpanzees, and apes; and a human,also denoted specifically as a “human subject”.

An inventive device illustratively operates by providing a force tocounteract fluid collection or flow along a percutaneousinstrument-tissue interface. It is common for fluid to develop in thespace surrounding a percutaneous instrument often beginning immediatelyafter insertion. The presence of this fluid allows migration, flow, orother penetration of agents normally excluded by the intact skin toareas below the skin. The penetration by these agents may lead todevelopment of infectious disease, inflammation at the site ofinsertion, or other unwanted complications.

As used herein, an “insertion site” is defined as an intentionalinterruption of skin or other tissue for the placement of a medicalappliance.

A force is illustratively a vacuum. A vacuum illustratively preventsfluid from moving along an interface between tissue and the embeddedcatheter or other instrument. The negative pressure of the vacuum allowsthe natural pressures of biological material or other atmosphericpressure to move unwanted material away from the areas at or below thesite of insertion.

An inventive device includes one or more sleeves. A sleeve is optionallyan inner sleeve or an outer sleeve. As used herein, the terms “inner”and “outer” are relative terms in terms of encompassing relativedimensions and should not be construed contextually as to positioningrelative to the epidermis. An inner sleeve is optionally made of aporous material or scaffold that is optionally penetrated by fluids orgasses. A scaffold is optionally a tissue scaffold that allows orpromotes attachment of cells, illustratively, fibroblasts to the surfaceof an inner sleeve. An inner sleeve is optionally treated. An innersleeve treatment illustratively includes compounds or surface texturesthat promote attachment of fibroblasts or other cellular material.Optionally, the inner sleeve is made of a woven material. A wovenmaterial is optionally penetratable by cells, fluids, gas, or othermaterials.

It is appreciated that an inner sleeve is optionally the only sleevepresent in the device. An inner sleeve is optionally a porous scaffoldthat is suitable for moving fluid or gas through the sleeve away fromthe surrounding environment. Materials operable for use as an innersleeve illustratively include: collagen, PEBAX, nylons, polypropylenes,polyurethanes, polyethylenes (HDPE, UHWPE, LDPE, or any blend of theaforementioned polyethylenes), PET, NiTi, MYLAR, Nickel Titanium Alloy,other polymers such as other thermoplastic polymers, fabrics, siliconessuch as silicone rubber, latex, glass, or other materials known in theart. It is appreciated that polymeric materials with a gradient ofcross-linking density through the material afford certain advantageswith respect to promoting vacuum or hydrodynamic draw and fibroblastinfiltration. By way of example, a polymer having a greater rigidityproximal to the central axis of the device relative to the distalsurface inhibits pressure differential induced collapse. In someembodiments, an inner sleeve is made from chemically inert material. Insome embodiments, the porous scaffold is in direct contact with the skinof the subject or traverses the skin of the subject. In some embodimentsan inner sleeve is textured or woven in such a way so as to provideattachment sites for fibroblasts. A texture is optionally a nanotexture.Illustrative nanotextures have pore sizes that are uniformly less than500 nanometers to provide an anchor point for a fibroblast pseudopodextension, while having dimensions that disfavor bacterial colonization.A nanotextured surface as used herein has features indentations of from50 to 500 nanometer median dimension. In some embodiments, theindentations have a median dimension of between 100 and 300 nanometers.

In some embodiments, a texture is in the form of a scaffold. A scaffoldis illustratively formed of gold. A gold scaffold is optionally formedby making a sleeve from a gold/silver alloy that is dipped in an acidsuch as a mineral acid which selectively dissolves the silver leaving agold structure with appropriate porosity. Alternatively, a scaffold isformed from an acid etchable, biocompatible nanocrystal such as silveror silica is dispersed in a polymer melt such as polycarbonate and aneck either formed directly therefrom, or the nanocrystal-doped polymeris coated onto a neck substrate. Through subjecting thenanocrystal-doped polymer to an acid or base solution, depending on thesolubility of the nanocrystal, voids are formed in the polymerreflective of the original nanocrystal dopant. For instance, silver isreadily dissolved in 6 N hydrochloric acid while silica is dissolved inconcentrated hydrofluoric acid. Dissolution in the presence ofsonication is appreciated to facilitate the process. Nanocrystal loadingof 1 to 10 percent by weight, depending on the specific nanocrystaldimensions, is sufficient to achieve the desired uniformity and densityof pores. Other porous surfaces and methods of manufacture areillustrated in U.S. Pat. No. 7,704,225 and references cited therein,each of which are incorporated herein by reference in their entirety.

It is appreciated that an inner sleeve is optionally coated orimpregnated with a first compound. Coating or impregnating optionallyprovides lubrication so as to ease insertion of the instrument into theskin. A compound optionally: is antibacterial such as those described inWO 2008/060380, the contents of which are incorporated herein byreference; resist or promote cellular adhesion; are anticoagulants orprocoagulants; or other desirable compound.

A compound optionally includes factors operable to selectively promotefibroblast growth and/or decrease attachment of bacteria or othercontaminants. A compound optionally promotes growth of cells such asfibroblasts. A coating optionally includes the compound fibroblastgrowth factor (FBF). Optionally, FBF is used in a coating along withinsulin and/or dexamethasone. The presence of dexamethasone and/orinsulin will promote multiple layer growth of fibroblasts on the surfaceof or within the pores of a sleeve. Coating substances illustrativelyinclude cell growth scaffolding matrices as detailed in U.S. Pat. Nos.5,874,500; 6,056,970; and 6,656,496; and Norman et al. Tissue Eng.3/2005, 11(3-4) pp. 375-386, each of which is incorporated herein byreference. An exemplary coating is a tissue scaffolding, poly-pxylylene, parylene and chemical modified versions of such coatings toenhance post-insertion stabilization. Chemical modificationsillustratively include bonding of fibronectin and other moleculesimplicated in the healing process. While tissue scaffolding and polymersare readily applied by painting, dip coating and spraying, it is alsoappreciated that polymeric coating are also readily applied by gas phasedeposition techniques such as chemical vapor deposition (CVD). A coatingis optionally porous in order to enhance capillary draw. In someembodiments a coating is biodegradable. A coating optionally has porestypically of an average size of between 10 and 500 microns, optionally,of an average size of between 30 and 50 microns.

An inventive device optionally includes an outer sleeve. An outer sleevefunctions to segregate or deliver vacuum draw pressure to an innersleeve. The outer sleeve optionally circumferentially and longitudinallycovers an inner sleeve. This configuration optionally shields the innersleeve from epidermal bacterial or other agents upon insertion.

An outer sleeve is optionally tapered at one or both ends. Tapering at adistal end (the end nearest the internal end of the catheter during use)provides improved insertion of the instrument into the skin of asubject. A taper may form a smooth interaction with the catheter at theouter sleeve distal end or a ridge is optionally present at or near thesite of device interaction with the catheter.

An outer sleeve is optionally made of any material suitable for use witha percutaneous instrument. Illustrative materials operable for an outersleeve include such materials that have a memory or are self-expanding.Materials operable for use as an outer sleeve illustratively include:PEBAX, nylons, polyurethanes, polyethylenes (HDPE, UHWPE, LDPE, or anyblend of the aforementioned polyethylenes), PET, NiTi, MYLAR, NickelTitanium Alloy, other polymers such as other thermoplastic polymers,fabrics, silicones such as silicone rubber, latex, glass, or othermaterials known in the art. An outer sleeve optionally includes or isformed of a scaffold. An outer sleeve scaffold is optionally made of thesame or different material as an inner sleeve scaffold. Scaffoldsoperable for an inner sleeve are similarly operable for an outer sleeve.

An outer sleeve is optionally expandable. An expandable outer sleeve isoptionally by stretch of the material, unfolding of the materialillustratively like of an accordion or other mechanism, or material thatwill provide expandability or compressibility to the outer sleeve.

It is appreciated that an outer sleeve is optionally coated orimpregnated with a second compound. A second compound is optionally thesame as a first compound. Coating or impregnation optionally provideslubrication so as to ease insertion of the instrument into the skin. Acompound optionally: is an antibacterial coating or impregnated materialsuch as those described in WO 2008/060380, the contents of which areincorporated herein by reference compounds to resist or promote cellularadhesion; anticoagulants or procoagulants; or other desirable compound.

In some embodiments, an outer sleeve is textured. A texture isoptionally formed of a tissue scaffold. A texture on an outer or innersleeve optionally has pore sizes, ridges, depressions, indentations, orother texture that is uniform or non-uniform. A texture is optionally ofa depth less than 500 nanometers to provide an anchor point for afibroblast pseudopod extension, while having dimensions that disfavorbacterial colonization. A nanotextured surface as used herein has auniform distribution of 50 to 500 nanometer median dimensionindentations. In some embodiments, the indentations have a mediandimension of between 100 and 300 nanometers.

In some embodiments an outer sleeve surrounds an inner sleeve. The outersleeve and inner sleeve are optionally formed from a unitary piece ofmaterial. The outer sleeve is optionally oriented surrounding an innersleeve and optionally is slidably positionable about an inner sleeve. Insome embodiments an outer sleeve protects an inner sleeve upon insertionof the inventive instrument and is positionally adjusted relative to theinner sleeve illustratively to a mark or other region that is optionallypositioned above the epidermis. In some embodiments the inner sleeveremains traversing the skin while the outer sleeve is positioned abovethe epidermis or penetrates to one or more desired depths or levels.

An outer sleeve is optionally positioned external to the skin or nearthe surface of the skin when the device is employed. It is appreciatedthat an outer sleeve optionally forms an upper chamber that providesuniform distribution of vacuum pressure into and throughout the innersleeve or the upper surface thereof.

An outer sleeve optionally terminates in or is integral with a collar. Acollar is optionally in fluidic connection with a conduit. In someembodiments a collar is made of a material with increased rigidityrelative to an outer sleeve.

An inventive device is optionally manufactured as a separate assembly orunitary piece so as to be associatable with a catheter prior toplacement across the skin. An inventive device is optionally formed witha slot to accept a catheter or other instrument. An instrument isoptionally slidable onto a catheter prior to inserting the catheterthrough the skin. Optionally, a catheter serves as a guide for aninventive instrument such that the instrument is slid onto a catheterfollowing catheterization into the same insertion location. Engagementof the instrument prevents agents from entering the insertion point orwill remove agents already in or under the insertion point.

In some embodiments, an inventive device is integral with a catheter orother percutaneous instrument.

An inventive complete instrument optionally includes a gasket, aconduit, a valve, and a vacuum source.

Without intending to be bound to a particular theory, a surface of aninventive device in contact with compromised skin for device insertionpromotes intercalation of fibroblasts regardless of whether the surfaceis textured, coated, or a combination thereof so as to simultaneouslypromote orthological changes in the fibroblast from circulatory form todendritic and/or stellate forms through a depth of more than one layerof fibroblast at a time and preferably more than five layers offibroblasts simultaneously anchoring to the device and more preferablymore than ten such layers of fibroblasts. Fibroblast orthologicalchanges simultaneously in more than one layer of such cells serve torapidly stabilize the percutaneous inventive device. In conjunction withthe vacuum pressure draw during the process, infection risks areminimized and an inventive device is stabilized against pullout or otherdevice motions relative to the surrounding dermal layers.

An inventive device optionally includes one or more gaskets or seals. Aseal prevents vacuum pressure from escaping to the atmosphere or fromdrawing bodily fluid into the system from the subcutaneal end of theinstrument. A gasket is optionally made from any material suitable forcreating a seal around the circumference of a catheter. A gasket isillustratively made from silicon rubber, latex, nylon, or otherpolymeric materials. A gasket is optionally connected to or integralwith an outer sleeve, an inner sleeve, a bandage, or a collar.

A conduit is optionally fluidly connected to an inner sleeve either viaa gasket or direct connection. A conduit is optionally made of anymaterial that will resist total collapse under vacuum pressures usedwith the invention.

A conduit is optionally transected by a valve. A valve is operable toengage, disengage, or adjust the vacuum pressure translated to the innersleeve. A valve is optionally mechanically or electrically controlled.Any valve or valve system known in the art is operable herein. A valveis optionally positioned at the junction between the conduit and theinstrument portions of the inventive device.

An inventive device is optionally connected to a vacuum source. A vacuumsource can be any source operable for creating negative pressure in oraround the device. A vacuum source is optionally a passive vacuum suchas a vacuum tube or bottle, or an active vacuum source illustratively amechanical pump, a syringe, or other vacuum source. A vacuum sourceoptionally applies a continuous or intermittent negative pressure. Themagnitude of the negative pressure is optionally adjustable, constant,or variable. In some embodiments an intermittent vacuum is used.Alternatively, a hydrodynamic draw agent is provided that draws fluidfrom the tissue surrounding through the sleeve via the conduit. Ahydrodynamic draw source illustratively includes a super absorbentpolymer such as sodium polyacrylate, polyacrylamide copolymer, ethylenemaleic anhydride copolymer, cross-linked carboxymethylcellulose,polyvinyl alcohol copolymers, cross-linked polyethylene oxide, andstarch grafted copolymer of polyacrylonitrile; high osmotic pressurecompositions, such as water soluble salts; and capillary flow drawagents such as dry silica, or other dry hydrophilic powders suchcellulosic material.

The inventive device optionally includes a blood or other fluiddetection system. A blood detection system is optionally a fluid sensingdevice. A fluid sensing device will optionally shut down the inventivedevice or reduce the negative pressure should too high a level of fluidpass through the conduit or otherwise into or around the inventivedevice. In some embodiments a fluid detection system will adjust thevacuum level to maintain fluid flow at a constant or variable rate.Should blood or other bodily fluid be detected at too high a rate, adetection system optionally reduces the vacuum level so as to reduce therate or adjust type of fluid flow.

An inventive instrument optionally includes a bandage. A bandageillustratively forms a seal on the surface of the skin. In someembodiments a bandage forms a chamber on the surface of the skinsurrounding the inner or outer sleeve. Although it is not absolutelynecessary, a chamber allows rapid and uniform application of a vacuumpressure around the circumference of a catheter. A bandage is optionallya polymeric material, cloth, or other material known in the art.

In some embodiments an inventive device does not penetrate the skin. Abandage optionally is associated with a gasket or is itself made ofmaterial that is operable to itself function as a gasket around acatheter. The bandage is optionally made of material with sufficientrigidity so as not to totally collapse under the negative pressure of avacuum on the epidermal side of the bandage. The bandage is optionallycircular in outer or inner shape. This circular shape is entirelyoptional. Other shapes such as triangular, square, oval, or polygonalare similarly operable.

An inventive device is optionally a bandage surrounding a catheter orother instrument wherein the bandage is in fluidic communication with avalve or conduit. A negative pressure applied on the epidermal side ofthe bandage is optionally of sufficient force to seal the outercircumference of the bandage to the epidermal layer. The presence of thevacuum itself is optionally sufficient to reduce or eliminate movementof agents into the skin of the subject at the site of the catheter.

An optional adhesive is present on the bandage or on the epidermis forcontact with the bandage. Adhesives are materials known in the art.Optionally, a bandage is integral with an instrument.

A diffuser or other porous material optionally surrounds a catheter andoptionally rests on the epidermal layer. The device is optionallymaintained in position by an adhesive that surrounds the catheterforming a seal sufficient to allow a vacuum to form around the insertionpoint. Alternatively, the vacuum itself produces a sufficient sealaround the circumference of the instrument or between the epidermis anda diffuser to both hold it one or both in place and provide sufficientpressure to draw the device onto the skin surrounding the catheter.

In some embodiments several device diameters are operable. An inventivedevice optionally has an inner diameter and an outer diameter. The innerdiameter of the device is optionally associated with the diameter of thepercutaneous instrument. A larger percutaneous instrument generally willrequire a larger inner diameter of the device. Alternatively, a singleinner diameter device is produced with removable and replaceable gasketsor seals that allow a wide range of catheter diameters or shapes to beused with the device.

In some embodiments the instrument is reusable. An inventive device isoptionally autoclavable or otherwise sterilizable.

A system for reducing or eliminating catheter related infection is alsoprovided. A system illustratively includes a plurality of inventivedevices. A plurality of devices are optionally connected to a singlevacuum source or a plurality of vacuum sources. A plurality of vacuumsources is optionally interconnected or otherwise simultaneously orindividually adjustable to increase or decrease the vacuum pressure atone or more sites of catheter insertion.

A process for reducing, preventing, reversing, treating, or eliminatinginfection at a percutaneous insertion point is also provided. Aninventive process illustratively includes applying a vacuum pressurearound the circumference of a catheter or other percutaneous instrument.The vacuum pressure causes fluid to move away from the subdermal layerspreventing infectious agents from entering the subdermal layer orpreventing additional infectious agents from entering the region duringtreatment for catheter related infection.

An inventive device is shown generally at 10 in FIG. 1 and shows asleeve 12 in fluid communication with the bore 14 of the conduit 16. Thesleeve 12 is formed of materials as detailed above with respect to theinner sleeve and is characterized by a porous matrix 18 adjacent to aperforated outer surface 20 of the conduit 16. In operation, porousmatrix 18 experiences strong vacuum or hydrodynamic forces created by avacuum or hydrodynamic draw source, collectively depicted at 22.Suitable average pore diameters are typically between The matrix 18 hasa rigidity sufficient to prevent collapse under the draw pressure as anoperative requirement and thereby maintain vacuum or hydrodynamicthrough the matrix. A highly cross-linked polymeric substance, collagen,porous ceramic or metallic substances are particularly well suited toform matrix 18. A matrix 18 is appreciated to promote vacuum draw, suchlarge pores are sized such that both bacteria and fibroblasts readilyinfiltrate such pores. Without intending to be bound by a particulartheory, it is believed that deleterious agents within the matrix 18 areactively drawn into the conduit bore 14 or if capable of biologicalmultiplication, inhibited from doing so by the forces exerted thereon bythe source 22. The distal surface 24 of the sleeve 12 has an optionalnanotexture 25, as detailed above to promote fibroblast pseudopodextension adherence yet are sufficiently small to discourage bacterialcolonization. It is appreciated that the surface 24 experiences limiteddraw from the source 22. Optionally, an intermediate matrix 26 isprovided between the matrix 18 and the surface 24. The matrix 26preferably has a reduced pore size compared to matrix 18 and thisattribute alone or in combination with a reduced cross-linking densityreduces the draw forces created by source 22 in this region compared tothat experienced in matrix 18. Alternatively, the matrix 26 has alike-pore size distribution relative to matrix 18, larger pore diametersrelative to matrix 18 or a graded pore dimension as a function ofthickness of matrix 26. The matrix 26 is formed of the same implantcompatible material as matrix 18 or another implant compatible material.To better depict the sleeve porosity, the right side of FIG. 1 onlyshows a single pore of matrix 26 in fluid communication with pore ofmatrix 18. A higher degree of pore collapse associated with vacuum drawthrough the matrix 26 is not only tolerated but is believed to promoterapid stabilization of the device 10. Accordingly, a program of sourcedraw is optionally provided that varies the strength of the vacuum orosmotic pressure applied to the matrix 18 and by extension to matrix 26as a function of time. The pore size in optional matrix 26 is of a sizethat allows circulating fibroblasts to infiltrate matrix 26 and therebyinitiate the healing process through formation of an interconnectednetwork of fibroblasts and other cells and compounds needed for tissuegranulation. Typical cross-sectional dimensions of pores in the matrix26 are between 3 and 50 circulating fibroblast diameters. It is furtherappreciated that the infiltration of the matrix 26 by fibroblastsoperative to dimensionally extend the device stabilization from a singlelayer of fibroblasts seen in a non-porous surface implant to a regioncorresponding to the thickness of the matrix 26. One of skill in the artwill appreciate that the strength of the vacuum or osmotic draw fromsource 22 is readily adjusted to promote infiltration into optionalmatrix 26 to speed stabilization. It is appreciated that the applicationof draw forces via source 22 in addition to inhibiting agents andpromoting fibroblast infiltration also serves the tissue-scale functionof adhering the body tissue T surrounding the device 10 in a fixedposition in contact with device 10 so as to form a stable interfacetherebetween. The resulting interface is superior for the granulationprocess relative to conventional sutures or adhesive bandages. It isappreciated that the matrix 18 and the matrix 26 with a nanotexturedsurface 24 are integral, or alternatively are formed as contiguousseparate layers as detailed above with respect to inner and outersleeves. A coating substance 27 optionally overcoats the surface 24,with coating substances illustratively include cellular ingressscaffolding, as will be further detailed below. The coating substancehave a tissue contacting surface 29 that is optionally nanotextured.

An inventive device is further detailed in FIG. 2 generally at 30 wherelike numerals correspond to the meaning imparted thereto with respect tothe aforementioned figure and specification text. Device 30 has acentral medical appliance that is depicted as a cannula 34 shown in thecontext of providing fluid communication between a medical appliance 34with subject vein V. The medical instrument 34 illustratively includes acatheter, cannula, pin, or wire or other percutaneous instrument withspecific versions thereof including a Steinman pin and a Kirschner wire.The device 30 is percutaneous through the epidermis, dermis, andsubcutaneous layers that are denoted at E, D, and S, respectively. Thedevice 30 has an inner sleeve 12a that corresponds to sleeve 12 detailedwith respect to FIG. 1 with the exception of varying in dimensionality.The inner sleeve 12a has a porous matrix 18 in fluid communication withthe vacuum or hydrodynamic draw source 22. Matrix 26 is optionallypresent intermediate between matrix 18 and surface 24. Preferably, acoating substance 27 overlies the surface 24. An outer sleeve 36 engagesthe medical appliance 34 at a vacuum seal 36 and forms fluidcommunication with a vacuum or hydrodynamic draw source 22 via conduit38. The outer sleeve 33 of device 30 is shown in FIG. 2 as the outersleeve 33 wholly enveloping inner sleeve 12a and serves as an introducerpreventing the transmission of skin bacteria to the wound created byplacement of the device 30 and after positioning as shown in FIG. 2, theouter sleeve 33 is retracted relative to the appliance 34 and innersleeve 12a to a position preferably just above epidermis E therebyallowing the source 22 to draw fluid through the then exposed surface 24and that of an optional coating 27 to the surrounding tissue as well asthe draw created source 22. It is appreciated that the relativedimensions of attributes depicted in FIG. 2 are distorted for visualclarity.

An inventive device is depicted in FIG. 3 generally at 40 where likenumerals correspond to the meaning ascribed thereto in theaforementioned figures. The device 40 varies from that depicted in FIG.2 only in that the outer sleeve 44 is preformed to not extend the fulllinear extent of the inner sleeve 12a and instead forms an insertionstop against the epidermis, E.

FIG. 4 is a perspective, partial cutaway view of an inventive device 50in which like numerals having the meanings ascribed thereto in theaforementioned figures. Percutaneous medical appliance 34 has a vacuumseal or gasket at 36 between a conduit 56 and a medical appliance 34.The conduit 56 is in fluid communication with an inner sleeve 12b thatis otherwise the same as sleeves 12 and 12a except for dimensionality.It is appreciated that inner sleeve 12b optionally includes matrix 26thereover, a coating substance 27, or a combination thereof. Vacuum orhydrodynamic draw of the inner sleeve 12b by a conduit 56 requiresvacuum draw to be precluded from region 57 of porous inner sleeve 12bdenoted at 57. Preferential vacuum draw through region 57 relative tosubdermal portions of inner sleeve 12b is accomplished through adherenceof a gas-tight bandage 59 to the outer surface of the epidermis E. It isappreciated that bandage 59 is used as a substitute for, or incombination with, an outer sleeve 54 forming a gas-tight seal withconduit 56 so as to achieve fluid communication between a source 22 andthe subcutaneous portions of inner sleeve 12b. Optionally, a diffuserconstituting an open cell foam material or woven material 51 ispositioned intermediate between the outer surface of the epidermis E andthe bandage 59 to moderate vacuum draw therethrough.

An inventive device is shown generally at 50′ in FIG. 5, where likenumerals used therein have the meaning ascribed thereto with respect tothe aforementioned figures. The device 50′ has all the attributes ofdevice 50 save for an outer sheath 54′ having an expanded bellows-likeconstruct providing a mode of varying the linear extent of the outersleeve 54′. It is appreciated that the conduit 56 is readily constructedto be slidable relative to appliance 34 and in conjunction with outersleeve 54′.

FIG. 6 is a cross-sectional view of an inventive device, shown generallyat 60, where like numerals have the meaning ascribed thereto withrespect to the aforementioned figures. An inner sleeve 12b has a gasketor seal 36 around the appliance 34 that contacts the outer layer ofepidermis E. A diffuser in the form of an annulus surrounds the gasketand is sealed against drawing exogenous air to the source 22 via bandage59. A vacuum draw through subject tissue, optional coating 26 and viainner sleeve 12b, diffuser 51 through source 22 is depicted.

An inventive device is readily provided in the form of a kit with avariety of sizes of gaskets, bandages, and diffusers to provide askintight seal such that vacuum draw communication is produced betweenthe skin surrounding an inventive device through an inner sleeve to asource 22. FIGS. 7A and 7B depict an inventive device generally at 70and 80, respectively, where like numerals correspond to the meaningascribed thereto with respect to the aforementioned figures. A collarformed of a material such as silicone 72 or 82 has an annular splitallowing the collar to slide along the length of medical appliance 34and preferably remote from the surface of the epidermis E. A plasticbase 74 or 84 extends outward so that a bandage 59 is readily securedand sealed to the collar 72 or 82.

FIGS. 8A and 8B depict the percutaneous components of inventive devicewith relative dimensions of aspect exaggerated for visual clarity wherelike numerals have the meaning ascribed thereto with respect to theaforementioned figures. A flanged inner sleeve 12c has the sameattributes as inner sleeve 12, 12a, and 12c and varies thereform only inshape. The inner sleeve 12c is formed of materials as detailed above andis characterized by a large and rigid pore matrix 18 in fluidcommunication to a vacuum source 22. Sleeve 12c has a surface 24 thatoptionally nanotextured to promote fibroblast adhesion. The surface 24,like the surfaces of any of the aforementioned sleeves 12, 12a, or 12bis optionally decorated with has a pattern of contoured cell-conveyingchannels 82. It is appreciated that the channels can take a variety offorms. It is appreciated that an operative device typically would have apattern of channels 82 circumferentially decorating the surface 24.Channel patterns operative herein include any pattern that disfavorsbacterial pocket formation. The channel 82 is formed by methods such asimprinting, embossing, molding or machining into the sleeve 12c.Preferably, the sleeve 12c is a nanotextured and decorated with channels82. A channel 82 according to the present invention preferably hasdimensions on the order of two to ten times the diameter of a fibroblastthat is equivalent to 20 to 300 microns since a fibroblast has adiameter from 10 to 15 microns. More preferably, a channel 82 has awidth of between 30 and 120 microns. Most preferably, channel 82 isdevoid of discontinuities and acute angles that disfavor cellularplanarization and adhesion. A parabolic cross section is exemplary of achannel facilitating fibroblast growth. Preferably, the transitionbetween the channel 82 and the adjacent region of surface 24 is devoidof discontinuities and acute angles that disfavor cellular planarizationand adhesion. It is appreciated that inner sleeve 12b optionallyincludes matrix 26 thereover, a coating substance 27, or a combinationthereof. The tissue contacting surface 29 of substance 27 is optionallynanotextured. A velour 84 optionally encompasses a portion of the sleeve12c. The velour 84 is illustratively formed of DACRON®, or to theimplantable polymeric material. The velour 84 is also optionallybiodegradeable.

FIG. 9 depicts an inventive device generally at 100 where like numeralscorrespond to the meaning ascribed thereto with respect to theaforementioned figures. A cap 102 is formed of a material such assilicone, a polymer or a metal and serves to keep debris from enteringthe device 100. Preferably, the cap 102 is remote from the surface ofthe epidermis E. The medical appliance 34 depicted as a catheter andvacuum or hydrodynamic draw tubing 104 pass through complementaryopenings 106 and 108, respectively formed in the cap 102. The tubing 104provides fluid communication between a vacuum or hydrodynamic drawsource 22 and an inner sleeve 12d that has the same attributes as innersleeve 12, 12a, 12b, and 12c and varies thereform only in shape. Theinner sleeve 12d is formed of materials as detailed above and ischaracterized by a large and rigid pore matrix 18 in fluid communicationto a vacuum source 22 such that the source 22 draws tissue fluid andfibroblasts into the sleeve 12d. Sleeve 12d has a surface 24 thatoptionally nanotextured to promote fibroblast adhesion. The surface 24,like the surfaces of any of the aforementioned sleeves 12, 12a, or 12bis optionally decorated with has a pattern of contoured cell-conveyingchannels as shown in FIGS. 8A and 8B. It is appreciated that innersleeve 12d optionally includes matrix 26 thereover, a coating substance27, or a combination thereof. The coating 27 is appreciated to need notcover the entire surface 24. The tissue contacting surface 29 ofsubstance 27 is optionally nanotextured. A flange 112 is provided tostabilize the implanted device 100 within the subcutaneous layer S. Aflange 112 is constructed from materials and formed by methodsconventional to the art. For example, those detailed in U.S. Pat. Nos.4,634,422; 4,668,222; 5,059,186; 5,120,313; 5,250,025; 5,814,058;5,997,524; and 6,503,228.

Various modifications of the present invention, in addition to thoseshown and described herein, will be apparent to those skilled in the artof the above description. Such modifications are also intended to fallwithin the scope of the appended claims.

Patents and publications mentioned in the specification are indicativeof the levels of those skilled in the art to which the inventionpertains. These patents and publications are incorporated herein byreference to the same extent as if each individual application orpublication was specifically and individually incorporated herein byreference.

The foregoing description is illustrative of particular embodiments ofthe invention, but is not meant to be a limitation upon the practicethereof. The following claims, including all equivalents thereof, areintended to define the scope of the invention.

1. A process for stabilizing an implanted device in subject tissuecomprising: providing a device comprising: a conduit having a bore andan outer conduit surface, the outer conduit surface optionally beingnanotextured; and a sleeve in fluid communication with the bore or theouter conduit surface of said conduit, said sleeve formed of a materialscharacterized by a pore matrix through which vacuum or hydrodynamic drawis achieved, said sleeve optionally having a distal nanotexturedsurface; and drawing vacuum against the subject tissue at the insertionsite in subject tissue through said sleeve and said conduit or fluidfrom the insertion site through said conduit to draw fibroblasts intoand onto said sleeve to stabilize the implanted device.
 2. The processof claim 1 further comprising attaching fibroblasts to the nanotexturedsurface, the surface having nanopores.
 3. The process of claim 1 furthercomprising manifolding the vacuum or fluid draw along the surface, thesurface having channels, texturing and/or a porous covering.
 4. Theprocess of claim 1 further comprising coating the surface with ascaffold, collagen, compounds, or a combination thereof.
 5. The processof claim 4 wherein the coating step creates a discrete layer or agradient, the layers or the gradients varying in at least one ofmechanical, geometrical or biological properties.
 6. The process ofclaim 4 wherein the drawing step retains tissue defining the insertionsite is held against the device by the vacuum or the fluid draw.
 7. Theprocess of claim 1 wherein the drawing step conveys biological fluidsand/or bioburden from the insertion point into said conduit.
 8. Theprocess of claim 1 wherein the drawing step creates a compliant bridgebetween the device and the tissue.
 9. A process for reducing infectionat the site of percutaneous access in subject tissue comprising:inserting a percutaneous medical appliance; and applying a vacuumpressure or a hydrodynamic dressing surrounding an area around the siteof percutaneous access.
 10. A process for stabilizing an implanteddevice at a percutaneous insertion site in subject tissue comprising:providing a device comprising: a conduit having a bore and an outerconduit surface, the outer conduit surface optionally beingnanotextured; a sleeve in fluid communication with the bore or the outerconduit surface of said conduit, said sleeve formed of a materialscharacterized by a pore matrix through which vacuum or hydrodynamic drawis achieved, said sleeve optionally having a distal nanotexturedsurface, said sleeve being inhomogenous with respect to at least oneproperty of mechanical, geometrical, cross-linking, or biologicalproperties; and drawing vacuum or fluid from the insertion site throughconduit to draw fibroblasts into on onto said sleeve to stabilize theimplanted device.
 11. The process of claim 10 further comprisingattaching fibroblasts to the nanotextured surface, the surface havingnanopores.
 12. The process of claim 10 further comprising manifoldingthe vacuum or fluid draw along the surface, the surface having channels,texturing and/or a porous covering.
 13. The process of claim 10 furthercomprising coating surface with a scaffold, collagen, compounds or acombination thereof.
 14. The process of claim 10 wherein the coatingstep creates a discrete layer or a gradient, the layers or the gradientsvarying in at least one of mechanical, geometrical or biologicalproperties.
 15. The process of claim 10 wherein the drawing step retainstissue defining the insertion site is held against the device by thevacuum or the fluid draw.
 16. The process of claim 10 wherein thedrawing step conveys biological fluids and/or bioburden from theinsertion point into said conduit.
 17. The process of claim 10 whereinthe drawing step creates a compliant bridge between the device and thetissue.